Which form of energy is responsible for the primary energy output of the sun and other stars? (Points : 1)
chemical energy
nuclear energy
mechanical energy
electromagnetic energy

The energy that stars radiate originates as nuclear energy. The core of a star is a place where the pressure and temperature are so enormous that hydrogen nuclei are fused into helium nuclei ... the same process that causes the explosion of a "hydrogen" bomb.

Nuclear, because if you think of how you get sunburnt when in sun too long, the sun emits UV Rays (Ultraviolet Rays) which can be nuclear if too strong. I hope this helps!